Ferocious wind-driven wildfires tore across California on Thursday, forcing tens of thousands of residents to evacuate, destroying thousands of buildings, and causing a number of injuries.

In Butte County, north of Sacramento, a fire exploded to 20,000 acres by the evening as it swept into the town of Paradise, causing "massive devastation," Cal Fire spokesperson Scott McLean said. Acting Gov. Gavin Newsom declared a state of emergency.

Up to 30,000 people were forced to evacuate due to the blaze, dubbed the Camp fire, and hundreds of buildings were believed to be destroyed. Officials did not have a definitive count of structures lost due to the ongoing firefighting and evacuation effort.

The fire spread so quickly that residents, flushed out of their homes all at once, clogged the highways, according to the LA Times. Some even abandoned their vehicles in favor of fleeing the flames on foot.

“Watching the drivers that were trying to get away was horrifying because you could see their faces and how scared they were," Shaaron Vogel, a member of the nursing faculty at Butte College, told the Times. "It really brings it home how many lives it’s affected. And so fast."

Roughly 3,300 students, faculty, and staff evacuated from Paradise's 11 schools, according to CNN, driving north to the town of Chico in school buses and employees' cars.

The Adventist Health Feather River Medical Center and its associated clinics in Paradise were also forced to close and evacuate patients to other hospitals because of the fire.

As wildfires have grown more frequent and extreme in California, the utilities started preemptively shutting the power off to tens of thousands of homes as a precaution. Cal Fire investigators found power lines and associated equipment owned by Pacific Gas & Electric company started 16 fires in October 2017.

The utility notified customers it may cut off power to a wide swath of Northern California to prevent further damage from the Camp fire, and had already done so in Paradise and parts of Ventura County, according to its outage map. PG&E also shut off natural gas lines to 12,000 customers in Paradise, the LA Times reported.

Noah Berger / AP

The National Weather Service said the wildfires are the result of unseasonably warm November temperatures, dry vegetation, low humidity, and gusty offshore winds. Cal Fire warned about the extreme conditions Wednesday afternoon, urging people to be cautious with materials that could spark a fire.

A number of #wildfires started across #California on Thursday and unfortunately the outlook for Friday ranges from Elevated to Extreme. The combination of unseasonably warm conditions, dry fuels and low humidity with gusty offshore winds are creating very dangerous conditions. https://t.co/hoL7pBJl2u